1. Technical Field
The present invention relates to a variable wavelength interference filter, an optical module equipped with the variable wavelength interference filter, and an optical analysis device equipped with the optical module.
2. Related Art
In the past, there has been known a variable wavelength interference filter having reflecting films respectively disposed on surfaces of a pair of substrates, the surfaces being opposed to each other, so as to opposed to each other via a predetermined gap, and drive electrodes respectively disposed on the surfaces of the substrates, the surfaces being opposed to each other. In such a variable wavelength interference filter, a voltage is applied between the drive electrodes to thereby control the gap between the reflecting films using the electrostatic force.
In such a variable wavelength interference filter, it is required to form an extraction electrode, which extends from each of the drive electrodes, on each of the substrates, and to provide wiring for applying the voltage to the extraction electrodes. However, since the extraction electrodes are respectively disposed on the surfaces of the pair of substrates, the surfaces being opposed to each other, there is a problem that the wiring operation becomes difficult.
Therefore, there have been proposed various configurations with which such wiring operation can easily be performed (see, e.g., JP-A-2008-261951 (Document 1)).
The device described in Document 1 is a variable shape mirror provided with a mirror substrate and a wiring substrate. The variable shape mirror is provided with the mirror substrate and the wiring substrate opposed to each other. The mirror substrate is provided with a flexible thin film having a reflecting film formed on the surface not opposed to the wiring substrate, a film-side opposed electrode disposed on the surface of the flexible thin film, the surface being opposed to the wiring substrate, and mirror substrate-side bonding pads wired to the film-side opposed electrode. Further, the wiring substrate is provided with a wiring substrate-side opposed electrode opposed to the film-side opposed electrode, wiring substrate-side bonding pads wired to the wiring substrate-side opposed electrode, and external connecting pads connected to the wiring substrate-side opposed electrode. Further, the mirror substrate-side bonding pads and the wiring substrate-side bonding pads are mechanically and electrically bonded with Au bumps, respectively.
However, in the variable shape mirror described in Document 1 mentioned above, it is required to separately dispose electrically conductive intermediate members such as Au bumps in order to electrically connecting the mirror substrate-side bonding pads and the wiring substrate-side bonding pads, and there is a problem that it is not achievable to easily and reliably make these bonding pads electrically be connected to each other.